Current techniques for the preservation of fresh produce consist of temperature and/or pressure treatment or control, wax and similar coating techniques, synthetic polymer coating techniques, and polymer packaging.
Various coating compositions have been proposed, e.g., a petroleum solvent solution of a waxy film former and a fungicide (U.S. Pat. No. 4,006,259), a mixture of lard, tallow and lecithin applied in molten state (U.S. Pat. No. 4,207,347), hydrogenated jojoba oil (U.S. Pat. No. 4,356,197), a salt of carboxylic acid and an alkyl amine (U.S. Pat. No. 4,532,156), a 3% oil-in-water emulsion of hydrogenated vegetable oil, stearic acid and an anionic emulsifier (U.S. Pat. No. 4,649,057), the combination of a food acid, an edible reducing agent and a carbohydrate thickener followed by freezing (U.S. Pat. No. 4,751,091), a denatured proteinaceous solution of soybeans, wheat and corn (U.S. Pat. No. 5,128,159), simultaneously scrubbing and drenching with a liquid containing a fungicide (U.S. Pat. No. 5,148,738), a slurry consisting of by-products of the produce and certain sugars and acids (U.S. Pat. No. 5,364,648), a mixture of a polysaccharide polymer, a preservative, an acidulent and emulsifiers (U.S. Pat. Nos. 5,198,254 and 5,376,391), and a light-activated composition (U.S. Pat. No. 5,489,442).
Various forms of produce packaging are disclosed, by way of example, in U.S. Pat. Nos. 4,769,262; 5,030,510; 5,093,080; 5,160,768; 5,427,807; 5,547,693; and 5,575,418.
Some Russian and Japanese publications have proposed the use of polyvinyl alcohol as a gas barrier coating for produce, but few if any of these suggestions have found their way into the commercial market.
Applications Ser. No. 09/229,374, filed Jan. 13, 1999 now abandoned and allowed Ser. No. 09/461,124, filed Dec. 14, 1999, commonly owned by the assignee of this application, disclose a highly improved process for preserving fresh produce and coating compositions therefor comprised of substantially hydrolyzed cold water insoluble polyvinyl alcohol, low molecular weight cold water soluble starch, and surfactant. Optional additional ingredients are plasticizers, antimicrobials, and antifoaming agents. Preferably the starch is maltodextrin, the surfactant lecithin or dioctyl sodium sulfosuccinate, the antimicrobial methylparaben, and the plasticizer glycerin. However, in order to be effective in preserving fresh produce, the amount of polyvinyl alcohol required in the coating composition is deemed by regulatory authorities to render the coating nonedible for human consumption.